ZHCSDO4B May 2015 – May 2018
PRODUCTION DATA.
Several key parameters must be updated to align with a given application's battery characteristics. For highest accuracy gauging, it is important to follow-up this initial configuration with a learning cycle to optimize resistance and maximum chemical capacity (Qmax) values prior to sealing and shipping systems to the field. Successful and accurate configuration of the fuel gauge for a target application can be used as the basis for creating a "golden" file that can be written to all gauges, assuming identical pack design and Li-Ion cell origin (chemistry, lot, and so on). Calibration data is included as part of this golden file to cut down on system production time. If using this method, it is recommended to average the voltage and current measurement calibration data from a large sample size and use these in the golden file. Table 12 shows the items that should be configured to achieve reliable protection and accurate gauging with minimal initial configuration.
| NAME | DEFAULT | UNIT | RECOMMENDED SETTING |
|---|---|---|---|
| Design Capacity | 1000 | mAh | Set based on the nominal pack capacity as interpreted from the cell manufacturer's data sheet. If multiple parallel cells are used, should be set to N × Cell Capacity. |
| Design Energy Scale | 1 | — | Set to 10 to convert all power values to cWh or to 1 for mWh. Design Energy is divided by this value. |
| Reserve Capacity-mAh | 0 | mAh | Set to desired runtime remaining (in seconds/3600) × typical applied load between reporting 0% SOC and reaching Terminate Voltage, if needed. |
| Cycle Count Threshold | 900 | mAh | Set to 90% of configured Design Capacity. |
| Chem ID | 0100 | hex | Should be configured using TI-supplied Battery Management Studio (bqStudio) software. Default open-circuit voltage and resistance tables are also updated in conjunction with this step.
Do not attempt to manually update reported Device Chemistry as this does not change all chemistry information. Always update chemistry using the bqStudio software tool. |
| Load Mode | 1 | — | Set to applicable load model, 0 for constant current or 1 for constant power. |
| Load Select | 1 | — | Set to load profile which most closely matches typical system load. |
| Qmax Cell 0 | 1000 | mAh | Set to initial configured value for Design Capacity. The gauge will update this parameter automatically after the optimization cycle and for every regular Qmax update thereafter. |
| Cell0 V at Chg Term | 4200 | mV | Set to nominal cell voltage for a fully charged cell. The gauge will update this parameter automatically each time full charge termination is detected. |
| Terminate Voltage | 3200 | mV | Set to empty point reference of battery based on system needs. Typical is between 3000 and 3200 mV. |
| Ra Max Delta | 44 | mΩ | Set to 15% of Cell0 R_a 4 resistance after an optimization cycle is completed. |
| Charging Voltage | 4200 | mV | Set based on nominal charge voltage for the battery in normal conditions (25°C, and so on). Used as the reference point for offsetting by Taper Voltage for full charge termination detection. |
| Taper Current | 100 | mA | Set to the nominal taper current of the charger + taper current tolerance to ensure that the gauge will reliably detect charge termination. |
| Taper Voltage | 100 | mV | Sets the voltage window for qualifying full charge termination. Can be set tighter to avoid or wider to ensure possibility of reporting 100% SOC in outer JEITA temperature ranges that use derated charging voltage. |
| Dsg Current Threshold | 60 | mA | Sets threshold for gauge detecting battery discharge. Should be set lower than minimal system load expected in the application and higher than Quit Current. |
| Chg Current Threshold | 75 | mA | Sets the threshold for detecting battery charge. Can be set higher or lower depending on typical trickle charge current used. Also should be set higher than Quit Current. |
| Quit Current | 40 | mA | Sets threshold for gauge detecting battery relaxation. Can be set higher or lower depending on typical standby current and exhibited in the end system. |
| Avg I Last Run | –299 | mA | Current profile used in capacity simulations at onset of discharge or at all times if Load Select = 0. Should be set to nominal system load. Is automatically updated by the gauge every cycle. |
| Avg P Last Run | –1131 | mW | Power profile used in capacity simulations at onset of discharge or at all times if Load Select = 0. Should be set to nominal system power. Is automatically updated by the gauge every cycle. |
| Sleep Current | 15 | mA | Sets the threshold at which the fuel gauge enters SLEEP mode. Take care in setting above typical standby currents else entry to SLEEP may be unintentionally blocked. |
| Charge T0 | 0 | °C | Sets the boundary between charging inhibit and charging with T0 parameters. |
| Charge T1 | 10 | °C | Sets the boundary between charging with T0 and T1 parameters. |
| Charge T2 | 45 | °C | Sets the boundary between charging with T1 and T2 parameters. |
| Charge T3 | 50 | °C | Sets the boundary between charging with T2 and T3 parameters. |
| Charge T4 | 60 | °C | Sets the boundary between charging with T3 and T4 parameters. |
| Charge Current T0 | 50 | % Des Cap | Sets the charge current parameter for T0. |
| Charge Current T1 | 50 | % Des Cap | Sets the charge current parameter for T1. |
| Charge Current T2 | 50 | % Des Cap | Sets the charge current parameter for T2. |
| Charge Current T3 | 50 | % Des Cap | Sets the charge current parameter for T3. |
| Charge Current T4 | 0 | % Des Cap | Sets the charge current parameter for T4. |
| Charge Voltage T0 | 210 | 20 mV | Sets the charge voltage parameter for T0. |
| Charge Voltage T1 | 210 | 20 mV | Sets the charge voltage parameter for T1. |
| Charge Voltage T2 | 207 | 20 mV | Sets the charge voltage parameter for T2. |
| Charge Voltage T3 | 205 | 20 mV | Sets the charge voltage parameter for T3. |
| Charge Voltage T4 | 0 | 20 mV | Sets the charge voltage parameter for T4. |
| Chg Temp Hys | 5 | °C | Adds temperature hysteresis for boundary crossings to avoid oscillation if temperature is changing by a degree or so on a given boundary. |
| Chg Disabled Regulation V | 4200 | mV | Sets the voltage threshold for voltage regulation to system when charge is disabled. It is recommended to program to same value as Charging Voltage and maximum charge voltage that is obtained from Charge Voltage T0–4 parameters. |
| CC Gain | 10 | mΩ | Calibrate this parameter using TI-supplied bqStudio software and calibration procedure in the TRM. Determines conversion of coulomb counter measured sense resistor voltage to current. |
| CC Delta | 10 | mΩ | Calibrate this parameter using TI-supplied bqStudio software and calibration procedure in the TRM. Determines conversion of coulomb counter measured sense resistor voltage to passed charge. |
| CC Offset | –1418 | Counts | Calibrate this parameter using TI-supplied bqStudio software and calibration procedure in the TRM. Determines native offset of coulomb counter hardware that should be removed from conversions. |
| Board Offset | 0 | Counts | Calibrate this parameter using TI-supplied bqStudio software and calibration procedure in the TRM. Determines native offset of the printed circuit board parasitics that should be removed from conversions. |
| Pack V Offset | 0 | mV | Calibrate this parameter using TI-supplied bqStudio software and calibration procedure in the TRM. Determines voltage offset between cell tab and ADC input node to incorporate back into or remove from measurement, depending on polarity. |